This invention relates to tires having a reinforcement formed from a continuous sheathed filament running diagonally over the tread region and alternating from one tire foot to the other. This invention also relates to a process for the production of cast tires reinforced with cord threads.
British Patent 562,137 describes a tire, in which sheathed filaments are worked into a rubber carcass for reinforcement purposes. The filaments are positioned around the bead. This publication does not suggest how a cast tire which is equipped with sheathed filament as the reinforcement could be produced.
U.S. Pat. No. 3,578,057 describes a plastic pneumatic tire of polyurethane elastomer for very high internal pressures, which is produced in a casting process using a mold and a mold core ring, and which has reinforcing inserts. The reinforcing inserts are designed as partially sheathing the mold core. A spacing layer ensures that the windings of the reinforcing insert have a spacing from the inside surface of the tire and are thus completely sheathed by the elastomer. In this tire, each reinforcing thread only contacts the tire foot at one point. In this case, the tire foot is a weak point. It is not known how the reinforcing insert might be joined in a force-locking manner to the edge of any bead which may be present. (There is no bead edge described in this reference). Under a considerable strain, this tire first fails in the tire foot.
Proceeding from a tire of the type described in U.S. Pat. No. 3,578,057, an object of the present invention is to improve the design of the reinforcement in the tire foot, and to provide a process which allows an economic production of such tires.